Superabsorbent Materials Comprising Peroxide

ABSTRACT

This invention pertains to a polymeric composition and an antimicrobial composition, each comprising a superabsorbent polymer (SAP), such as used in diapers and sanitary napkins, and peroxide. The superabsorbent material can be made by the process of treating a preformed SAP, such as a crosslinked polyacrylate salt, with a treatment solution comprising hydrogen peroxide dissolved in water, followed by drying. The resulting superabsorbent material has strong antimicrobial activity. Optionally, the treatment solution may also contain a metal salt, including those of zinc, zirconium, and magnesium.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of our co-pendingInternational Patent Application, Serial Number PCT/US2010/024635, filedFeb. 18, 2010, which is a non-provisional application of U.S.Provisional Patent Application 61/153,464 filed Feb. 18, 2009. Thisapplication claims benefit of priority to both prior applications. Theentire disclosures of each of the aforementioned applications areincorporated herein by reference.

TECHNICAL FIELD

This invention pertains to antimicrobial superabsorbent materials.

BACKGROUND ART

Water-absorbing resins are widely used in sanitary goods, diapers,hygienic goods, wiping cloths, packaging materials, water-retainingagents, dehydrating agents, sludge coagulants, disposable towels andbath mats, disposable door mats, thickening agents, disposable littermats for pets, condensation-preventing agents, and release controlagents for various chemicals. Water-absorbing resins are available in avariety of chemical forms, including substituted and unsubstitutednatural and synthetic polymers, such as hydrolysis products of starchacrylonitrile graft polymers, carboxymethylcellulose, crosslinkedpolyacrylates, sulfonated polystyrenes, hydrolyzed polyacrylamides,polyvinyl alcohols, polyethylene oxides, polyvinylpyrrolidones, andpolyacrylonitriles.

Such water-absorbing resins are termed “superabsorbent polymers,” orSAPs, and typically are lightly crosslinked hydrophilic polymers. SAPsare materials that imbibe or absorb at least 10 times their own weightin aqueous fluid and that retain the imbibed or absorbed aqueous fluidunder moderate pressure. The imbibed or absorbed aqueous fluid is takeninto the molecular structure of the SAP rather than being contained inpores from which the fluid could be eliminated by squeezing. Some SAPscan absorb up to 1,000 times their weight in aqueous fluid. SAPs aregenerally discussed in Goldman et al. U.S. Pat. Nos. 5,669,894 and5,559,335, and by Mitchell in U.S. Pat. No. 7,249,632, the disclosuresof which are incorporated herein by reference. SAPs can differ in theirchemical identity, but all SAPs are capable of absorbing and retainingamounts of aqueous fluids equivalent to many times their own weight,even under moderate pressure. For example, SAPs can absorb one hundredtimes their own weight, or more, of distilled water. The ability toabsorb aqueous fluids under a confining pressure is an importantrequirement for an SAP used in a hygienic article, such as a diaper.

Rebre, in U.S. Pat. Nos. 5,442,014 and 5,373,066, describes thetreatment of a certain superabsorbent polymer (“SAP”) with hydrogenperoxide during its manufacture. Treatment with hydrogen peroxideapparently reduces the residual monomer content in the SAP product to anacceptable level. The amount of hydrogen peroxide is from 0.08% to 0.19%by weight relative to the dry SAP polymer.

Metal peroxides, or complexes of metallic salts and hydrogen peroxide(“HP”), have been mentioned as antimicrobial treatments for textiles.These compositions may be formed by the reaction of metal salts such aszinc acetate, with hydrogen peroxide in aqueous solution (U.S. Pat. Nos.5,656,037; 5,152,996; 4,199,322; and 4,174,418).

The industry of superabsorbents (SAPs) is very often confronted with aneed to add other properties to these products in addition to theirabsorption and retention performance qualities. For example, when theabsorbent article in place is impregnated with bodily fluids, inparticular urine, it gives off powerful and unpleasant odors, e.g.ammoniacal odors arising from the hydrolysis of urea by the bacterialureases present on the skin and in the digestive tract. With the aim ofeliminating these odors from certain SAP products, certain antiodoradditives have been taught. Thus, WO 98/20915 and EP 739 635 describemixtures containing, respectively, zeolites and borax. U.S. Pat. No.4,842,593 describes diapers containing SAP with pad agents and anontoxic, nonirritant and nonvolatile antimicrobial agent which is notincorporated in a non-leachable manner.

SUMMARY OF THE INVENTION

The present invention provides compositions, methods, and articles ofmanufacture. The compositions, desirably having antimicrobialproperties, may be made by treating a superabsorbent polymer (“SAP”)with hydrogen peroxide (“HP”). The treatment involves swelling thesuperabsorbent polymer with an aqueous solution of hydrogen peroxide,followed by drying the polymer. This desirably produces a driedcomposition which is an antimicrobial superabsorbent polymer withnon-leaching antimicrobial properties.

The present invention utilizes the inventors' discovery that hydrogenperoxide seems to remain physically trapped in the dried SAP powdersafter treatment with HP. This has been substantiated by leaching studies(described below), which show that no antimicrobial effect is leachedinto solution when the treated powders are placed into an excess ofsaline solution. However, iodometric titration of the treated SAPmaterials in aqueous solution indicates the presence of active peroxide.Microorganisms such as bacteria are destroyed upon contact with thetreated SAP materials. These observations suggest that HP is sequesteredin the treated SAP, and released upon demand (i.e. by contact of thetreated SAP with either microorganisms, or reagents that are reactivewith the sequestered HP).

The antimicrobial compositions of this invention resulting from thetreatment of a superabsorbent polymer with hydrogen peroxide areheat-stable, and have good shelf life.

It is an embodiment of the invention to provide a polymeric compositionhaving sequestered peroxide, produced by treating a superabsorbentpolymer with at least 0.005 grams of hydrogen peroxide per gram ofsuperabsorbent polymer, wherein the treatment comprises swelling thesuperabsorbent polymer with a treatment solution comprising aqueoushydrogen peroxide, followed by drying. In a preferred embodiment of theinvention the superabsorbent polymer is treated with 0.005 to 0.2 gramsof hydrogen peroxide per gram of superabsorbent polymer. In a morepreferred embodiment of the invention, the superabsorbent polymer istreated with 0.01 to 0.15 grams of hydrogen peroxide per gram ofsuperabsorbent polymer. In an even more preferred embodiment of theinvention, the superabsorbent polymer is treated with 0.02 to 0.15 gramsof hydrogen peroxide per gram of superabsorbent polymer.

It is an embodiment of the invention that the treatment solution furthercomprises a metal salt, in an amount suitable to treat thesuperabsorbent polymer with at least 0.02 grams of the metal salt pergram of superabsorbent polymer. Suitable metal salts include zinc,magnesium, silver, copper, and zirconium salts. It is preferred that themetal salt is an acetate salt, such as zinc acetate, zinc acetatedihydrate, magnesium acetate, and zirconium acetate. More preferred arethe salts, zinc acetate or magnesium acetate.

It is an embodiment of the invention that the superabsorbent polymer bea carboxylate-containing polymer, a cellulose derivative, apolyacrylamide, or a polydiallyldialkylammonium salt. In a preferredembodiment of the invention the superabsorbent polymer is acarboxylate-containing polymer. In a more preferred embodiment of theinvention the carboylate-containing polymer is an acrylic acid-basedpolymer. The acrylic acid-based polymer can also be a cross-linkedhydrophilic sodium salt form of a partially neutralized acrylic acidpolymer.

It is an embodiment of the invention that the polymeric compositionprepared from the superabsorbent polymers and treatment solutions issuperabsorbent.

It is an embodiment of the invention to provide a method of making theabove-disclosed polymeric compositions by a process comprising the stepsof

-   -   a. swelling a superabsorbent polymer with a treatment solution        comprising hydrogen peroxide, and    -   b. drying the polymer,        whereby hydrogen peroxide is sequestered within or on the        surface of the superabsorbent polymer.

It is an embodiment of the invention to provide an antimicrobialcomposition produced by treating a superabsorbent polymer with at least0.005 grams of hydrogen peroxide per gram of superabsorbent polymer,wherein the treatment comprises swelling the superabsorbent polymer withan aqueous treatment solution of hydrogen peroxide, followed by drying,whereby contact with the antimicrobial composition provides at least a 3log reduction in viable bacteria. In a preferred embodiment of theinvention the superabsorbent polymer is treated with 0.005 to 0.2 gramsof hydrogen peroxide per gram of superabsorbent polymer. In a morepreferred embodiment of this invention, the superabsorbent polymer istreated with 0.01 to 0.15 grams of hydrogen peroxide per gram ofsuperabsorbent polymer. In an even more preferred embodiment of theinvention the superabsorbent polymer is treated with 0.02 to 0.15 gramsof hydrogen peroxide per gram of superabsorbent polymer.

It is an embodiment of the invention that the treatment solution furthercomprises a metal salt, in an amount suitable to treat thesuperabsorbent polymer with at least 0.02 grams of the metal salt pergram of superabsorbent polymer. Suitable metal salts include zinc,magnesium, silver, copper, and zirconium salts. It is preferred that themetal salt is an acetate salt, such as zinc acetate, zinc acetatedihydrate, magnesium acetate, and zirconium acetate. More preferred arethe salts, zinc acetate or magnesium acetate.

It is an embodiment of the invention that the superabsorbent polymer isa carboxylate-containing polymer, a cellulose derivative, apolyacrylamide, or a polydiallyldialkylammonium salt. In a preferredembodiment of the invention the superabsorbent polymer is acarboxylate-containing polymer. In a more preferred embodiment of theinvention the carboxylate-containing polymer is an acrylic acid-basedpolymer. The acrylic acid-based polymer can also be a cross-linkedhydrophilic sodium salt form of a partially neutralized acrylic acidpolymer.

It is an embodiment of the invention that the antimicrobial compositioncomprise superabsorbent polymer in the form of a powder or granularmaterial. It is an embodiment of the invention that the antimicrobialcomposition prepared from the superabsorbent polymers and treatmentsolutions is superabsorbent. It is an embodiment of the invention thatthe antimicrobial activity of the antimicrobial composition isnon-leachable.

It is an embodiment of the invention to provide a bandage, wounddressing, tampon, sanitary napkin, diaper, wipe, incontinence device orgarment, food packaging, or medical device, comprising an antimicrobialcomposition of the invention. It is a preferred embodiment of theinvention to provide a method of controlling diaper rash by using adiaper or incontinence garment comprising an antimicrobial compositionof the invention.

It is an embodiment of the invention to provide a method of making theabove-disclosed superabsorbent antimicrobial compositions by a processcomprising the steps of

-   -   a. swelling a superabsorbent polymer with a treatment solution        comprising hydrogen peroxide, and    -   b. drying the polymer,        whereby a superabsorbent polymer having non-leachable        antimicrobial activity is produced.

It is an embodiment of the invention to provide a method of disinfectingan infected liquid to produce a 3-log reduction in viable bacteriacontain therein. The method steps comprise contacting the liquid with anantimicrobial composition comprising a superabsorbent polymer treatedwith a treatment solution comprising peroxide, and optionally a metalsalt, and drying the produced antimicrobial composition. In a preferredembodiment of the invention the method reduces or controls odor,infection, microbial rashes, or allergies.

It is an embodiment of the invention that the treatment solution is atleast 5 times the weight of the superabsorbent polymer.

It is an aspect of this invention to provide a method of inhibiting theproliferation of microorganisms by using a superabsorbent antimicrobialcomposition resulting from the treatment of a superabsorbent polymerwith hydrogen peroxide, wherein the treatment comprises swelling thesuperabsorbent polymer with an aqueous solution of hydrogen peroxide,followed by drying of the polymer to produce a superabsorbentantimicrobial composition.

It is an aspect of this invention to provide a method of reducing odorand simultaneously controlling diaper rash by the suppression ofbacteria that attack urinary urea with the liberation of ammonia byimpregnating the diaper fabric with an effective amount of anantimicrobial composition resulting from the treatment of asuperabsorbent polymer with hydrogen peroxide, wherein the treatmentcomprises swelling the superabsorbent polymer with an aqueous solutionof hydrogen peroxide, followed by drying of the polymer.

It is therefore an aspect of the present invention to providecompositions, methods of treatment, and articles of manufacture, whereinthere is employed an antimicrobial composition resulting from thetreatment of a superabsorbent polymer with hydrogen peroxide, whereinthe treatment comprises swelling the superabsorbent polymer with anaqueous solution of hydrogen peroxide, followed by drying of thepolymer.

It is also an aspect of the present invention to provide compositions,methods of treatment, and articles of manufacture, wherein there isemployed an antimicrobial superabsorbent composition resulting from thetreatment of a superabsorbent polymer with hydrogen peroxide, whereinthe treatment comprises swelling the superabsorbent polymer with anaqueous solution of hydrogen peroxide, followed by drying of polymer,for the purpose of providing the benefits of odor reduction, control ofmicrobes, and reduction of infection or microbial rashes and allergies.

It is also an aspect of the present invention to provide anantimicrobial superabsorbent composition resulting from the treatment ofa cross-linked hydrophilic sodium salt form of a partially neutralizedacrylic acid-based polymer with hydrogen peroxide, wherein the treatmentcomprises swelling the superabsorbent polymer with an aqueous solutionof hydrogen peroxide, followed by drying of the polymer.

It is also an aspect of the present invention to provide a method ofinhibiting the proliferation of microorganisms by using an antimicrobialsuperabsorbent composition resulting from the treatment of across-linked hydrophilic sodium salt form of a partially neutralizedacrylic acid-based polymer with hydrogen peroxide, wherein the treatmentcomprises swelling the superabsorbent polymer with an aqueous solutionof hydrogen peroxide, followed by drying of the polymer.

It is also an aspect of the present invention to provide a method ofreducing odor and simultaneously controlling diaper rash by thesuppression of bacteria that attack urinary urea with the liberation ofammonia by impregnating a diaper with an effective amount of acomposition for controlling the spread of infection, the compositionbeing an antimicrobial superabsorbent composition resulting from thetreatment of a cross-linked hydrophilic sodium salt form of a partiallyneutralized acrylic acid-based polymer with hydrogen peroxide, whereinthe treatment comprises swelling the superabsorbent polymer with anaqueous solution of hydrogen peroxide, followed by drying of thepolymer.

It is therefore an aspect of the present invention to providecompositions, methods of treatment, and articles of manufacture, whereinthere is employed an antimicrobial superabsorbent composition resultingfrom the treatment of a cross-linked hydrophilic sodium salt form of apartially neutralized acrylic acid-based polymer with hydrogen peroxide,wherein the treatment comprises swelling the superabsorbent polymer withan aqueous solution of hydrogen peroxide, followed by drying of thepolymer.

It is also an aspect of the present invention to provide compositions,methods of treatment, and articles of manufacture, wherein there isemployed an antimicrobial superabsorbent composition resulting from thetreatment of a cross-linked hydrophilic sodium salt form of a partiallyneutralized acrylic acid-based polymer with hydrogen peroxide, whereinthe treatment comprises swelling the superabsorbent polymer with anaqueous solution of hydrogen peroxide, followed by drying of thepolymer, for the purpose of providing the benefits of odor reduction,control of microbes, and reduction of infection or microbial rashes andallergies.

It is also an aspect of the present invention to provide a method ofinhibiting the proliferation of microorganisms by using an antimicrobialsuperabsorbent composition resulting from the treatment of across-linked hydrophilic sodium salt form of a superabsorbent polymerwith hydrogen peroxide and optionally, a metal salt, wherein thetreatment comprises swelling the superabsorbent polymer with an aqueoussolution of hydrogen peroxide and metal salt, followed by drying of thepolymer.

It is also an aspect of the present invention to provide a method ofreducing odor and simultaneously controlling diaper rash by thesuppression of bacteria that attack urinary urea with the liberation ofammonia by impregnating the diaper with an effective amount of acomposition for controlling the spread of infection, the compositionbeing an antimicrobial superabsorbent composition resulting from thetreatment of a superabsorbent polymer with hydrogen peroxide andoptionally, a metal salt, wherein the treatment comprises swelling thesuperabsorbent polymer with an aqueous solution of hydrogen peroxide andmetal salt, followed by drying of the polymer.

It is therefore an aspect of the present invention to providecompositions, methods of treatment, and articles of manufacture, whereinthere is employed an antimicrobial superabsorbent composition resultingfrom the treatment of a superabsorbent polymer with hydrogen peroxideand optionally, a metal salt, wherein the treatment comprises swellingthe superabsorbent polymer with an aqueous solution of hydrogen peroxideand metal salt, followed by drying of the polymer.

It is also an aspect of the present invention to provide compositions,methods of treatment, and articles of manufacture, wherein there isemployed an antimicrobial superabsorbent composition resulting from thetreatment of a superabsorbent polymer with hydrogen peroxide andoptionally, a metal salt, wherein the treatment comprises swelling thesuperabsorbent polymer with an aqueous solution of hydrogen peroxide andmetal salt, followed by drying of the polymer, for the purpose ofproviding the benefits of odor reduction, control of microbes, andreduction of infection or microbial rashes and allergies.

It is also an aspect of the present invention to provide anantimicrobial superabsorbent composition resulting from the treatment ofa cross-linked hydrophilic sodium salt form of a partially neutralizedacrylic acid-based polymer with hydrogen peroxide and optionally, ametal salt, wherein the treatment comprises swelling the superabsorbentpolymer with an aqueous solution of hydrogen peroxide and metal salt,followed by drying of the polymer.

It is also an aspect of the present invention to provide a method ofinhibiting the proliferation of microorganisms by using an antimicrobialsuperabsorbent composition resulting from the treatment of across-linked hydrophilic sodium salt form of a partially neutralizedacrylic acid-based polymer with hydrogen peroxide and optionally, ametal salt, wherein the treatment comprises swelling the superabsorbentpolymer with an aqueous solution of hydrogen peroxide and metal salt,followed by drying of the polymer.

It is also an aspect of the present invention to provide a method ofreducing odor and simultaneously controlling diaper rash by thesuppression of bacteria that attack urinary urea with the liberation ofammonia by impregnating the diaper with an effective amount of acomposition for controlling the spread of infection, the compositionbeing an antimicrobial superabsorbent composition resulting from thetreatment of a cross-linked hydrophilic sodium salt form of a partiallyneutralized acrylic acid-based polymer with hydrogen peroxide andoptionally, a metal salt, wherein the treatment comprises swelling thesuperabsorbent polymer with an aqueous solution of hydrogen peroxide andmetal salt, followed by drying of the polymer.

It is therefore an aspect of the present invention to providecompositions, methods of treatment, and articles of manufacture, whereinthere is employed an antimicrobial superabsorbent composition resultingfrom the treatment of a cross-linked hydrophilic sodium salt form of apartially neutralized acrylic acid-based polymer with hydrogen peroxideand optionally, a metal salt, wherein the treatment comprises swellingthe superabsorbent polymer with an aqueous solution of hydrogen peroxideand metal salt, followed by drying of the polymer.

It is also an aspect of the present invention to provide compositions,methods of treatment, and articles of manufacture, wherein there isemployed an antimicrobial superabsorbent composition resulting from thetreatment of a cross-linked hydrophilic sodium salt form of a partiallyneutralized acrylic acid-based polymer with hydrogen peroxide andoptionally, a metal salt, wherein the treatment comprises swelling thesuperabsorbent polymer with an aqueous solution of hydrogen peroxide andmetal salt, followed by drying of the polymer, for the purpose ofproviding the benefits of odor reduction, control of microbes, andreduction of infection or microbial rashes and allergies.

In an embodiment of this invention a superabsorbent polymer is treatedwith an aqueous treatment solution.

It is an advantage of this invention that a strong or mineral acid isnot required to catalyze the reaction of the SAP with hydrogen peroxidein order to form a superabsorbent antimicrobial composition.

It is an embodiment of this invention that the superabsorbent materialbe dried immediately after swelling of the superabsorbent polymer withthe treatment solution.

In an embodiment of this invention the superabsorbent material is storedafter swelling with the treatment solution for a predetermined length oftime at a predetermined temperature before drying, in order to allow thetreatment solution to react with the polymer.

In a preferred embodiment of this invention, the superabsorbent polymeris a cross-linked hydrophilic sodium salt form of a partiallyneutralized acrylic acid-based polymer.

In an embodiment of this invention, enough treatment solution is appliedto uniformly wet the superabsorbent polymer.

In an embodiment of this invention the minimum amount of treatmentsolution is applied which results in uniform wetting of thesuperabsorbent polymer, as this requires the least energy input toeffect drying of the treated material. It is not necessary that thesuperabsorbent polymer absorb the entire treatment solution which isapplied.

In an embodiment of this invention the treatment solutions comprisingaqueous hydrogen peroxide and metal salts further comprise an acid addedto enhance solubility of the metal salt and hydrogen peroxide mixture inthe aqueous treatment solution. A preferred acid for this purpose isacetic acid.

In an embodiment of this invention, at least 0.02 grams of metal saltper gram of superabsorbent polymer is used; in a more preferredembodiment of this invention at least 0.05 grams of metal salt per gramof superabsorbent polymer is used; and in a most preferred embodiment,at least 0.10 grams of metal salt per gram of superabsorbent polymer isused.

It is an aspect of this invention that after treatment of thesuperabsorbent material with the treatment solution, the treatedmaterial be dried.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a diaper in accordance with the present invention.

FIG. 2 is a cross-sectional view of the absorbent pad 1 shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Definitions

“Microbe” or “microorganism” refers to any organism or combination oforganisms such as bacteria, viruses, protozoa, yeasts, fungi, molds, orspores formed by any of these.

“Antimicrobial” refers to the microbicidal or microbistatic propertiesof a compound, composition, article, or material that enables it tokill, destroy, inactivate, or neutralize a microorganism; or to preventor reduce the growth, ability to survive, or propagation of amicroorganism.

“Substrate” refers to a surface or medium upon which an antimicrobial,such as a peroxide, is chemically bonded. Alternatively, a substrate isa surface, object, or material which is reacted with a reagent, such ashydrogen peroxide, to produce an antimicrobial composition, orantimicrobially-modified substrate. In the case of the presentinvention, the substrate is a superabsorbent polymer.

“Surface” refers to the common outside surface of the substrate (asuperabsorbent polymer in this case), and also to the internal surfacesof voids, channels, or pores within the substrate.

By “inherently antimicrobial” is meant a property of a material whereinthe material would exhibit antimicrobial activity or properties in theabsence of any antimicrobial activity or properties contributed byagents, compounds, or additives which are not integral to the material,not chemically bonded to the material, or detachable from the material,or after the removal or depletion of such agents, compounds, oradditives from the material. “Inherently antimicrobial” does not meanthat the material contains no leachable agents with antimicrobialactivity.

By “non-leaching” is meant that the antimicrobial peroxides of thepresent invention, once attached to the material or substrate via themethod of the current invention, do not appreciably separate from,migrate out of, or away from the material or substrate, enter a wound,or otherwise become non-integral with the material or substrate understandard uses. By “not appreciably separate” is meant that no more thanan insubstantial amount of antimicrobial peroxide separates, for exampleless than one percent, preferably less than 0.1 percent, more preferablyless than 0.01 percent, and even more preferably less than 0.001 percentof the total quantity of antimicrobial peroxide. Alternatively, “notappreciably separate” means that the solution concentration ofantimicrobial peroxide resulting from separation of attachedantimicrobial peroxide, in a liquid in contact with the material orsubstrate, does not exceed a predetermined level, for example less than0.01%, preferably less than 0.005%, and more preferably less than0.001%. Alternately, depending on the application, “not appreciablyseparate” may mean that no adverse effect on wound healing or the healthof an adjacent tissue of interest is measurable. It should be understoodthat particular definition may depend on the application in which theinvention is used. For medical applications such as wound dressings, theoverriding concern would be to ensure that the localized concentrationof leachable material remains below a specific level at a given point intime, or leads to no adverse effects over the period of use.

A non-leaching antimicrobial composition may be classified as“inherently antimicrobial”, in that the composition possessesantimicrobial properties without the addition of a separateantimicrobial agent. Generally, the term non-leaching would be appliedonly to a solid composition. Non-leaching properties manifest twodistinct benefits. First, the level of antimicrobial in the compositionis not reduced or diluted by contact with fluids. In other words, theantimicrobial cannot be washed-out and depleted. Second, theantimicrobial will remain bound to the composition and not betransferred to the surrounding environment, where it may haveundesirable effects. An example is a wound dressing, where leaching ofantimicrobial into the wound might cause cellular toxicity or interferewith healing.

By “superabsorbent polymer”, or “SAP”, is meant a polymeric materialthat imbibes or absorbs at least 10 times its own dry weight in aqueousfluid and that retains the imbibed or absorbed aqueous fluid undermoderate pressure. The imbibed or absorbed aqueous fluid is taken intothe SAP rather than being contained in macroscopic pores from which thefluid could be eliminated by squeezing. Examples of SAPs include, butare not limited to acrylate and methacrylate polymers. Goldman et al.(U.S. Pat. Nos. 5,669,894 and 5,559,335) and Mitchell (U.S. Pat. No.7,249,632) generally discuss superabsorbent polymers. The disclosures ofthese patents are incorporated by reference herein except whereinconsistent with the present disclosure.

“Acrylic acid-based polymer” means a polymer formed by thepolymerization of acrylic acid or a derivative thereof such asmethacrylic acid, or, alternatively, the fully- or partially-neutralizedsalts of such a polymer. The acrylic acid-based polymer may becrosslinked and/or may be hydrophilic.

As used herein, the term “SAP particles” refers to superabsorbentpolymer particles in the dry state, i.e., particles containing from nowater up to an amount of water less than the weight of the dryparticles. The term “particles” refers to granules, fibers, flakes,spheres, powders, platelets, and other shapes and forms known to personsskilled in the art of superabsorbent polymers. The terms “SAP gel” and“SAP hydrogel” refer to a superabsorbent polymer in the hydrated state,i.e., particles that have absorbed at least their weight in water, andtypically several times their weight in water. The term “surfacecrosslinking” means that the level of functional crosslinks in the SAPparticle in the vicinity of the surface of the particle is generallyhigher than the level of functional crosslinks in the SAP particle inthe interior of the particle. The term “surface-crosslinked SAPparticle” refers to an SAP particle having its molecular chains presentin the vicinity of the particle surface cross-linked by a compoundapplied to the surface of the particle.

Initially, the swelling capacity of an SAP particle on contact withliquids, also referred to as free swelling capacity, was the main factorin the design and development of SAP particles. Later, however, it wasfound that not only is the amount of absorbed liquid important, but thestability of the swollen gel, or gel strength, also is important. Thefree swelling capacity on one hand, and the gel strength on the otherhand, represent contrary properties. Accordingly, SAP particles having aparticularly high absorbency typically exhibit a poor gel strength, suchthat the gel deforms under pressure (e.g., the load of a body), andprevents further liquid distribution and absorption.

A balanced relation between absorptivity (gel volume) and gel strengthis desired to provide proper liquid absorption, liquid transport, anddryness of a diaper and the skin when using SAP particles in a diaper.In this regard, not only is the ability of SAP particles to retain aliquid under subsequent pressure an important property, but absorptionof a liquid against a simultaneously acting pressure, i.e., duringliquid absorption also is important. This is the case in practice when achild or adult sits or lies on a sanitary article, or when shear forcesare acting on the sanitary article, e.g., leg movements. This absorptionproperty is referred to as absorption under load.

Investigators have researched various methods of improving the amount ofliquid absorbed and retained by SAP particles, especially under load,and the rate at which the liquid is absorbed. One preferred method ofimproving the absorption and retention properties of SAP particles is tosurface crosslink the SAP particles.

As understood in the art, surface-crosslinked SAP particles have ahigher level of crosslinking in the vicinity of the surface than in theinterior. As used herein, “surface” describes the outer-facingboundaries of the particle. For porous SAP particles, exposed internalsurface also are included in the definition of surface.

Absorbent polymers capable of absorbing from about thirty to sixty gramsof water per gram of polymer are known, as is the use of such polymersin disposable diapers, sanitary napkins, surgical pads, and bath mats,for example. Particularly sought-after property is increased waterabsorbency. Polymers having this property often are referred to ashydrogels or superabsorbents. The nature and utility of superabsorbentsare illustrated by U.S. Pat. No. 4,449,977. According to this reference,a desirable feature of a superabsorbent is the presence of acrylate ormethacrylate groups which can be salts, amides, esters, or the freeacids. Many hydrogels are based on acrylate and methacrylate polymersand copolymers, for example, as shown in U.S. Pat. Nos. 2,976,576,3,220,960, 3,993,616, 4,154,898, 4,167,464, 4,192,727, 4,192,827, and4,529,739. Hydrogels based on starch or a modified starch are shown byU.S. Pat. Nos. 4,069,177, 4,076,663, 4,115,332, and 4,117,222. Otherhydrogels are based on poly(oxyalkylene) glycols as in U.S. Pat. No.3,783,872. Hydrogels prepared from hydrolyzed crosslinkedpolyacrylamides and crosslinked sulfonated polystyrenes are described inU.S. Pat. No. 4,235,237. Finally, polymers based on maleic anhydride aredescribed in U.S. Pat. Nos. 2,988,539, 3,393,168, 3,514,419, 3,557,067,and 4,401,793. U.S. Pat. No. 3,900,378 describes hydrogels fromradiation crosslinked blends of hydrophilic polymers and fillers. Suchcategory of absorbent polymers preferred in the present invention,however, can be exemplified by, for example, U.S. Pat. No. 3,966,679,which relates to acrylic acid-based water-swellable superabsorbentpolymers useful as catamenial tampons and diapers.

Hydrogen peroxide is favored in many applications because its breakdownproducts, water and oxygen, are innocuous, and it tends to have broadspectrum antimicrobial activity. Broad spectrum activity is important insituations where harmful organisms are present but their identity is notknown. Hydrogen peroxide is a well known antiseptic which has beenextensively employed in aqueous solution for the treatment of infectiousprocesses in both human and veterinary topical therapy. The agent can beused in its original form after suitable dilution, or it can be derivedfrom those solid compounds which form salts or additive compounds withhydrogen peroxide. Included among these are sodium perborate, sodiumcarbonate peroxide, sodium peroxyphosphate, urea peroxide, potassiumpersulfate, and others. When added to water, these compounds hydrolyzeinto hydrogen peroxide and the corresponding carrying salt. Theprincipal limitations of commonly used peroxide aqueous solutions,however, are their poor shelf stability caused by the decomposition ofhydrogen peroxide into gaseous oxygen and water at room temperature, andthe transitory contact of the active oxygenating agent with the affectedtissue. In addition, when such compositions are formed of additivecompounds with hydrogen peroxide, it is common to prepare the adductcomposition before incorporating it into the desired composition.

Blank, in U.S. Pat. Nos. 4,985,023, 4,990,338, 5,035,892, 5,045,322,5,061,487, and 5,079,004 describes an antimicrobial superabsorbentcomposition of a cross-linked hydrophilic sodium salt form of apartially neutralized acrylic acid-based polymer gel having covalentlybonded thereto a silane quaternary ammonium antimicrobial. Thecomposition can be in the form of flakes, strips, powders, filaments,fibers, or films, and may be applied to a substrate in the form of acoating. Quaternary ammonium antimicrobials are known to be veryeffective against many types of bacteria; however, they are generallyless effective against spores, fungi, and viruses.

Hobson, in U.S. Pat. No. 6,399,092 describes an anhydrous, hydrophilicwound dressing containing a superabsorbent polymer and an antimicrobialagent. Its anhydrous nature allows it, when applied to a wound site, toabsorb wound fluid and slowly release its water-soluble active microbialagent into the wound.

Each of the above-mentioned U.S. patents and U.S. patent applications ishereby incorporated by reference except where inconsistent with thetechnical disclosure herein.

DETAILED DESCRIPTION

The present invention includes an antimicrobial composition resultingfrom the treatment of a superabsorbent polymer (SAP) with a treatmentsolution comprising hydrogen peroxide (HP). The treatment includes thesteps of swelling the superabsorbent polymer with an aqueous solution ofhydrogen peroxide followed by drying of the polymer, whereby the driedcomposition is an antimicrobial superabsorbent polymer with non-leachingantimicrobial properties. The antimicrobial composition can optionallycomprise a metal ion.

The antimicrobial compositions may be prepared by the processesdisclosed herein. Commercially-available SAPs are treated with atreatment solution comprising hydrogen peroxide (HP). The SAP is allowedto absorb aqueous solutions of HP for a length of time that allows theHP solution to swell. The absorption step may be carried out at roomtemperature. Alternatively, higher or lower temperatures are suitablefor swelling the SAP. The treated SAP may be immediately dried or storedfor a predetermined length of time at a predetermined temperature beforedrying. Any temperature and time combination that results in thoroughdrying of the treated SAP may be used. One skilled in the art willrecognize that drying conditions may affect the absorbance properties(rate and extent) of the finished antimicrobial SAP product, and willemploy appropriate conditions to assure optimization of theseproperties, if necessary.

The inventors discovered that materials treated in this mannermaintained a residual antimicrobial capacity even after drying. Weexpected that HP would be completely removed from the SAP substrate bydrying because it is relatively volatile. However, a significant amountof antimicrobial effect was observed for the dried SAP materials aftertreatment with HP. It is believed that the antimicrobial effectexhibited by the dried SAP powder after treatment with HP is a result ofreaction between carboxylate groups of the SAP and hydrogen peroxide toform peracids (also known as peroxyacid or percarboxylic) groups, or thesodium salts thereof. However, such reactions normally require catalysts(such as a strong mineral acid), whereas on the contrary, no suchcatalyst is required in order to realize the residual antimicrobialeffect in the products of the current invention. Alternatively, HP isotherwise sequestered or bound in the treated SAP in a nonvolatile andnon-leaching manner, and HP becomes available on demand for oxidativereaction, or to function as an antimicrobial. The SAP, after treatmentor reaction with HP, followed by drying, is able to provide acontrolled-release, sustained-release, or on-demand-release of chemicaland biochemical properties normally associated with HP.

Antimicrobial compositions comprising metal salts can be prepared by avariation of the general procedure immediately above. Certain metalsalts (zinc acetate, for example) can be combined with HP in a treatmentsolution and used to treat a SAP material in order to impartantimicrobial properties to the SAP. In a typical procedure commerciallyavailable SAPs are allowed to absorb aqueous solutions of HP and themetal salt, followed by drying of the treated SAP materials. In somecases, the combination of HP and metal salt provides an enhancement ofantimicrobial effect compared to HP alone; however, it is found that themajor contribution to antimicrobial effectiveness is due to the HPcomponent, not the metal salt.

The inventors have prepared zinc-containing antimicrobial superabsorbentpolymers (SAPs) via a process wherein a solution of zinc salts mixedwith hydrogen peroxide (HP) is combined with a preformed SAP. Suitablezinc salts include zinc peroxide, zinc oxide, and zinc acetate (ZA). TheSAP was allowed to absorb the solutions and then dried. The processforms and traps metal peroxides or polymeric complexes derived from zincperoxide, zinc oxide, and zinc acetate within, and on the surface of,the SAP powder particles in order to produce a non-leachingantimicrobial superabsorbent composition.

In order to investigate the effect of different variables, (such asreagent combinations, ratios, and concentrations) experiments wereperformed using either zinc acetate combined with HP, zinc acetate alone(no HP), or hydrogen peroxide alone (no ZA). It is completely unexpectedthat any residual antimicrobial effect would be seen from SAP powderstreated only with hydrogen peroxide, as HP is volatile, and should becompletely removed form the substrate when it is dried. Surprisingly, asignificant amount of antimicrobial effect was observed even for the SAPmaterials treated with only HP (in the absence of zinc salts), and thiseffect was several orders of magnitude higher than for the materialprepared with only zinc acetate. It is presumed that the antimicrobialeffect exhibited by the dried SAP powder after treatment with hydrogenperoxide is a result of reaction between carboxylate groups of the SAPand hydrogen peroxide to form peracids (also known as peroxyacid orpercarboxylic) groups, or the sodium salts thereof. Alternatively, HPmay be otherwise sequestered in the treated SAP in a nonvolatile andnon-leaching manner, and available on demand for oxidative reaction, orto function as an antimicrobial.

In the above-mentioned experiments, SAP materials (crosslinked sodiumpolyacrylate powders) treated with a treatment solution comprising zincacetate and HP exhibited significant antimicrobial activity, showing a6.2 log reduction (full kill) when placed into 50 times their weight ofphosphate buffered saline containing approximately 1,000,000 cfu/mL ofE. Coli. When HP was omitted (zinc acetate only), the antimicrobialactivity decreased by a factor of more than 10,000 (only 1.8 logreduction). Surprisingly, when zinc acetate was omitted (HP-only), theantimicrobial activity remained very high (5.6 log reduction, or higherin some cases).

It is known in the art to use strong mineral acids to catalyze thereaction between hydrogen peroxide and a carboxylic acid in order toform a peracid. However, it was found that such acid catalysts are notrequired for the formation of useful antimicrobial superabsorbentcompositions via the reaction of a superabsorbent polymer and hydrogenperoxide. Indeed, most commercial SAP compositions are formulated to notgive an acidic pH when exposed to water, as the absorbent capacity of acarboxylate-based SAP is reduced at low pH. This may mean that theformation of peracid does not result from treatment of the SAP with HP.Regardless, antimicrobial activity is observed even after the treatedSAP substrate is dried. A complete understanding of the exact chemicalreactions and chemical species involved in this process is not necessaryto enable a person having ordinary skill in the art to practice theinvention.

It is an embodiment of the present invention to provide compositions,methods of treatment, and articles of manufacture, wherein there isemployed an antimicrobial superabsorbent composition resulting from thetreatment of a cross-linked hydrophilic sodium salt form of a partiallyneutralized acrylic acid-based polymer with hydrogen peroxide. Thetreatment comprises swelling the superabsorbent polymer with an aqueoustreatment solution comprising hydrogen peroxide, followed by drying ofpolymer, to produce a superabsorbent antimicrobial composition for thepurpose of providing the benefits of odor reduction, control ofmicrobes, and reduction of infection or microbial rashes and allergies.

It is also an embodiment of the present invention to providecompositions, methods of treatment, and articles of manufacture, whereinthere is employed an antimicrobial superabsorbent composition resultingfrom the treatment of a superabsorbent polymer with hydrogen peroxideand optionally, a metal salt, wherein the treatment comprises swellingthe superabsorbent polymer with an aqueous treatment solution comprisinghydrogen peroxide and metal salt, followed by drying of the polymer toproduce a superabsorbent antimicrobial composition.

In preferred embodiments of the aspects of the invention, the metal saltis chosen from the group comprising; salts of zirconium, zinc, copper,silver, or magnesium. In a more preferred embodiment, the metal salt isa zinc or magnesium salt. In a preferred embodiment of this invention,the metal salt is an acetate salt. In a most preferred embodiment ofthis invention, the metal salt is zinc acetate or magnesium acetate.

Superabsorbent polymer materials suitable for the practice of thisinvention include those which are soluble, insoluble, gels, powders,films, coatings, complexes, copolymers, fibers, etc. Exemplifyingsuperabsorbent polymer materials useful in the practice of thisinvention include carboxylate-containing polymer for example,polyacrylates, polymethacrylates, alginates, cellulose derivatives suchas carboxymethylcellulose, polylactides, polyglycolides,polysaccharides, or any polymer containing a carboxylate group. Othersuperabsorbent polymers such as those comprising polyacrylamides andpolydiallyldialkylammonium salts, such as polyDADMAC are also suitablefor the practice of this invention. The polymers may optionally havequaternary ammonium groups attached thereto.

In one embodiment of this invention, the superabsorbent polymer is inthe form of a powder or granular material. In a preferred embodiment ofthis invention, the superabsorbent polymer is a cross-linked hydrophilicsodium salt form of a partially neutralized acrylic acid-based polymer.

The antimicrobial superabsorbent compositions of the invention areuseful for reducing urinary odors, controlling diaper rash, reducing theproliferation of microorganisms, reducing of infection, microbialrashes, and allergies.

The antimicrobial compositions of this invention resulting from thetreatment of a superabsorbent polymer with hydrogen peroxide areheat-stable, and do not lose potency after storage for several months.

After treatment of the superabsorbent material with hydrogen peroxide,the treated material is dried. One skilled in the art will recognizethat drying conditions may affect the absorbance properties (rate andextent) of the finished antimicrobial SAP product, and will employappropriate conditions to assure optimization of these properties, ifnecessary.

One method of preparing the superabsorbent antimicrobial compositioncomprises the steps treating the a superabsorbent polymer with hydrogenperoxide, wherein the treatment comprises swelling the superabsorbentpolymer with an aqueous solution of hydrogen peroxide, followed bydrying of the polymer to produce a superabsorbent antimicrobialcomposition. The resulting superabsorbent antimicrobial compositioninhibits the proliferation of microorganisms

When diaper fabric is treated with an effective amount of anantimicrobial composition produced by the above described method,suppression of bacteria that attack urinary urea with the liberation ofammonia occurs resulting in a reduction in odors and control of diaperrash. Similarly, when articles of manufacture are prepared fromcomponents comprising an antimicrobial superabsorbent composition ofthis invention, the resulting article receives the benefits of odorreduction, control of microbes, and reduction of infection or microbialrashes and allergies.

Compositions, methods of treatment, and articles of manufacturecomprising a cross-linked acrylic acid-based polymer are within thescope of this invention. For example, an antimicrobial superabsorbentcomposition also results from the treatment of a cross-linkedhydrophilic sodium salt form of a partially neutralized acrylicacid-based polymer with hydrogen peroxide, wherein the treatmentcomprises swelling the superabsorbent polymer with an aqueous solutionof hydrogen peroxide, followed by drying of the polymer. Such anantimicrobial superabsorbent composition inhibits the proliferation ofmicroorganisms. It also reduces odor, and controls diaper rash bysuppressing bacteria that attack urinary urea with the liberation ofammonia. The compositions or the articles of manufacture comprising theantimicrobial composition provide the benefits of odor reduction,control of microbes, and reduction of infection or microbial rashes andallergies.

The antimicrobial superabsorbent composition may optionally comprise ametal salt. Such a composition is prepared by swelling thesuperabsorbent polymer with an aqueous solution of hydrogen peroxide andmetal salt, followed by drying of the polymer. The resulting compositionmay be used to provide methods of treatment, for example, a method ofinhibiting the proliferation of microorganisms, reducing odor, orcontrolling diaper rash by suppressing bacteria that attack urinary ureawith the liberation of ammonia. Articles of manufacture can be preparedfrom components comprising the antimicrobial superabsorbent compositionand optionally comprising a metal salt.

An antimicrobial superabsorbent composition of the invention maycomprise a cross-linked hydrophilic sodium salt form of a partiallyneutralized acrylic acid-based polymer and a metal salt. Such acomposition may be prepared by treating a cross-linked hydrophilicsodium salt form of a partially neutralized acrylic acid-based polymerwith hydrogen peroxide and a metal salt, wherein the treatment comprisesswelling the superabsorbent polymer with an aqueous solution of hydrogenperoxide and metal salt, followed by drying of the polymer. Theantimicrobial superabsorbent composition so prepared may be used toprovide methods of treatment, for example, a method of inhibiting theproliferation of microorganisms.

As a specific example, one of ordinary skill in the art may reduce odorof a diaper and simultaneously control diaper rash by impregnating thediaper with an effective amount of a composition for controlling thespread of infection. The antimicrobial composition in the treated diapersuppresses bacteria that attack urinary urea with the liberation ofammonia. Thus the antimicrobial compositions of the invention providethe benefits of odor reduction, control of microbes, and reduction ofinfection or microbial rashes and allergies. Articles of manufacture canbe prepared from the antimicrobial superabsorbent composition resultingfrom the treatment of a cross-linked hydrophilic sodium salt form of apartially neutralized acrylic acid-based polymer with hydrogen peroxideand a metal salt.

In an embodiment of this invention, the superabsorbent material isstored after swelling with the treatment solution for a predeterminedlength of time at a predetermined temperature before drying, in order toallow the treatment solution to react with the polymer.

In a preferred embodiment of this invention, enough treatment solutionis applied to uniformly wet the superabsorbent polymer.

In a preferred embodiment of this invention the minimum amount oftreatment solution is applied which results in uniform wetting of thesuperabsorbent polymer, as this requires the least energy input toeffect drying of the treated material. It is not necessary that thesuperabsorbent polymer absorb the entire treatment solution which isapplied.

In a preferred embodiment of this invention, the superabsorbent polymeris treated with at least 5 times it weight of treatment solution.

In a preferred embodiment of this invention the treatment solutioncomprises aqueous hydrogen peroxide.

In another embodiment of this invention, the treatment solutioncomprises aqueous hydrogen peroxide and a metal salt.

In a more preferred embodiment of this invention, the treatment solutioncomprises aqueous hydrogen peroxide and zinc acetate or hydrogenperoxide and magnesium acetate.

In an embodiment of this invention the treatment solutions comprisingaqueous hydrogen peroxide and metal salts further comprise an acid addedto enhance solubility of the metal salt and hydrogen peroxide mixture inthe aqueous treatment solution. A preferred acid for this purpose isacetic acid.

In an embodiment of this invention, at least 0.005 grams hydrogenperoxide per gram of superabsorbent polymer is used. In a preferredembodiment of this invention, at least 0.02 grams hydrogen peroxide pergram of superabsorbent polymer is used; in a more preferred embodimentof this invention at least 0.05 grams hydrogen peroxide per gram ofsuperabsorbent polymer is used; and in a most preferred embodiment, atleast 0.10 grams hydrogen peroxide per gram of superabsorbent polymer isused.

In a preferred embodiment of this invention, at least 0.02 grams ofmetal salt per gram of superabsorbent polymer is used; in a morepreferred embodiment of this invention at least 0.05 grams of metal saltper gram of superabsorbent polymer is used; and in a most preferredembodiment, at least 0.10 grams of metal salt per gram of superabsorbentpolymer is used.

It is an embodiment of this invention that after treatment of thesuperabsorbent material with the treatment solution, the treatedmaterial is dried. One skilled in the art will recognize that dryingconditions may affect the absorbance properties (rate and extent) of thefinished antimicrobial SAP product, and will employ appropriateconditions to assure optimization of these properties, if necessary.

Superabsorbent materials useful in the practice of this inventioninclude those which are soluble, insoluble, gels, powders, films,coatings, complexes, copolymers, fibers, etc. Superabsorbent materialsuseful in the practice of this invention include carboxylate-containingpolymer for example, polyacrylates, polymethacrylates, alginates,cellulose derivatives such as carboxymethylcellulose, polylactides,polyglycolides, polysaccharides, or any polymer containing a carboxylategroup.

It is an embodiment of this invention to provide a method ofdisinfecting a liquid to produce a 3-log reduction in viable bacteria inthe liquid, which comprises mixing the liquid with an antimicrobialcomposition resulting from the treatment of a superabsorbent polymerwith hydrogen peroxide, wherein the treatment comprises swelling thesuperabsorbent polymer with an aqueous solution of hydrogen peroxide,followed by drying of the polymer.

Numerous articles may be made of the antimicrobial SAP compositions ofthe present invention. For example, an article of manufacture of thepresent invention includes a bandage, wound dressing, tampon, sanitarynapkin, diaper, wipe, incontinence device or garment, food packaging,medical device, or other application where an antimicrobial SAP wouldprovide benefit.

As alternative embodiments of this invention, organic and inorganicperoxides may be employed in the practice of this invention instead ofhydrogen peroxide. Examples include: sodium peroxide, perborates,persulfates, sodium carbonate peroxide, sodium peroxyphosphate, ureaperoxide, benzoyl peroxide, t-butylhydroperoxide, and the like, whichmay be employed in various forms, such as neat, solutions, dispersions,suspensions, and the like.

In embodiment of this invention the dried antimicrobial superabsorbentmaterial is capable of effecting a reduction of viable bacteria when 0.2grams of the composition is added to approximately 11 mL of aqueousliquid which contains approximately 1,000,000 viable bacterialorganisms. In a preferred embodiment of this invention, the reduction ofviable bacteria is such that less than 1,000 viable organisms remain(3-log reduction). In a more preferred embodiment of this invention, thereduction of viable bacteria is such that less than 100 viable organismsremain (4-log reduction). In an even more preferred embodiment of thisinvention, the reduction of viable bacteria is such less than 10 viableorganisms remain (5-log reduction). In a most preferred embodiment ofthis invention, the reduction is such that zero viable organisms remain(6-log reduction, or full-kill). In a preferred embodiment of thisinvention, the reduction of viable bacteria occurs within 24 hours. In amore preferred embodiment of this invention, the reduction of viablebacteria occurs in less than 10 hours. In a still more preferredembodiment of this invention, the reduction of viable bacteria occurs inless than 4 hours. In a still more preferred embodiment of thisinvention, the reduction of viable bacteria occurs in less than 2 hours.In an even more preferred embodiment of this invention, the reduction ofviable bacteria occurs in less than 1 hour. In the most preferredembodiment of this invention, the reduction of viable bacteria occurs inless than 30 minutes.

It is an aspect of the inventive method to use any temperature and timecombination that results in thorough drying of the material. As usedherein, thoroughly dried means, for instance, that a substrate exposedto a solution of hydrogen peroxide is then dried to a constant weight.As used herein, dried to a constant weight means dried to the point atwhich continued application of the chosen drying procedure will nolonger result in a considerable additional measurable loss of weight dueto evaporation of water or other solvent. Attainment of constant weightis a useful tool to measure extent of dryness; however, the attainmentof constant weight is not the actual factor that enables non-leachableattachment of the antimicrobial to the substrate. The particulartemperatures and drying times necessary to achieve thorough dryingdepend, among other things, on the particular substrate material, theinitial amount of moisture in the article, the weight and size of thearticle, the amount of airflow provided to the article during drying,and the humidity of the air or other medium contacting the article. Anydrying apparatus, drying method, and temperature and drying timecombination that thoroughly dries the treated substrate is sufficient.For purposes of illustration, depending on the particularcharacteristics of a particular application, the drying step may beperformed in an oven (e.g. 80° C. for 2 hours), in a high throughputfurnace (e.g. 140° C. for 30 seconds), in a clothes dryer, in adesiccator, in a vacuum chamber, in a dehumidifier, in a dehydrator, orin a lyophilizer (freeze dryer). Infrared heat, radiant heat,microwaves, and hot air are all suitable drying methods for thesubstrate which has been exposed to the treatment solution. The upperlimit of drying temperature for a particular application will generallybe determined by the degradation temperature of the particular substrateor peroxide. Other drying methods such as supercritical fluid drying mayalso be successfully employed in the practice of this invention. Freezedrying may be used.

In the appended drawings, FIG. 1 shows a diaper 10, comprising anabsorbent pad 12 used to contain urine and other bodily wastes.

As shown in cross-section in FIG. 2, the pad 12 contains a top sheet 14and a back sheet 16. The liquid-absorbing layer 18 consists essentiallyof an antimicrobial composition as disclosed herein, comprising asuperabsorbent polymer, hydrogen peroxide, and optionally, a metal salt.Above the liquid-absorbing layer is a layer 20 containing fluff pulp forcomfort of the wearer.

EXAMPLES Example 1 Treatment of an Acrylate SAP with Zinc Acetate andHydrogen Peroxide (sample ZNP-1)

Twenty grams of an SAP powder (cross-linked hydrophilic sodium salt formof a partially neutralized acrylic acid-based polymer, similar toLuquasorb or HySorb materials manufactured by BASF) was added to asolution prepared by dissolving 4 grams of zinc acetate dihydrate(Aldrich Chemical catalog #383058) and 9.3 grams of hydrogen peroxide(35%, Aldrich Chemical catalog #349887) in 187.5 mL of deionized water.The mixture was stirred for a few minutes until all of the liquid wasabsorbed. The wet gel was spread onto a plastic dish and set in front ofan electric fan to dry at room temperature for three days. The driedmaterial was collected and lightly ground in a mortar and pestle to aconsistency resembling that of the starting SAP powder.

Example 2 Treatment of a SAP with Zinc Acetate and Hydrogen Peroxide(Sample ZNP-2B)

A procedure substantially similar to that described in Example 1 wasused, except that the zinc acetate and hydrogen peroxide concentrationswere lower. The treatment solution was prepared using 1.5 grams of zincacetate, 3.5 grams of HP and 195 mL of water.

Example 3 Treatment of a SAP with Zinc Acetate (Sample ZNP-2C)

The procedure of Example 2 was followed, except that the hydrogenperoxide was omitted.

Example 4 Treatment of a SAP with Hydrogen Peroxide (Sample ZNP-2D)

The procedure of Example 2 was followed, except that the zinc acetatewas omitted.

Example 5 Treatment of a SAP with Hydrogen Peroxide (Sample HP1-A)

The procedure of Example 4 was followed, except that 6 grams of hydrogenperoxide and 94 grams of deionized water were used.

Example 6 Treatment of a SAP with Hydrogen Peroxide (Sample HP1-B)

The procedure of Example 4 was followed, except that 6 grams of hydrogenperoxide and 94 grams of deionized water were used, and the sample wasdried in an oven set at 80° C. for 3 hours. Absorbance and antimicrobialefficacy results (see below) for the heat treated powders were notdifferent from the results for the powders dried at room temperature.This indicates good thermal stability for the compositions.

Example 7 Heat Treatment of an Antimicrobial SAP Powder

Samples of the materials prepared in Examples 2 and 4 were placed inuncovered beakers in an oven set at 60° C. for 72 hours to test thethermal stability of the antimicrobial SAP powders. Absorbance andantimicrobial efficacy results (see below) for the heat treated powderswere not different from the results for the as-produced powders. Thisindicates good thermal stability for the compositions.

Example 8 Treatment of Carboxymethylcellulose (CMC) with HydrogenPeroxide (Sample 121208C)

Ten grams of a carboxymethylcellulose (CMC) powder were treated with 50mL of solution prepared by mixing 5 grams of 35% HP with 45 mL ofdistilled water. The mixture was stirred and kneaded for several minutesuntil a uniform consistency was obtained. The resulting antimicrobialCMC composition was then air-dried for 72 hours and lightly ground witha mortar and pestle.

Example 9 Fluid Absorbance of the Antimicrobial SAP Materials Preparedin the above Examples

Each powder from Examples 1 to 8 was placed into a plastic centrifugetube with phosphate buffered saline (PBS, pH=7.4) at a ratio of 0.2grams of powder to 10 mL of PBS. The tubes were shaken and left to sitfor one hour. The tubes were shaken again and then centrifuged atapproximately 2000 rpm for ten minutes. The ratio of swollen SAP gel tosupernatant liquid in each tube was used to calculate the absorptioncapacity of the antimicrobial SAP powders. Untreated SAP powder absorbedapproximately 45 times its weight of PBS. The materials of the aboveExamples all absorbed at least 35 times their weight of PBS, with theexception of the material of Example 1, which only absorbed 30 times itsweight.

Example 10 Observation of Non-leaching Antimicrobial Effects

PBS solution removed from each tube prepared for the absorbance studiesdescribed in Example 9 was placed onto agar plates with freshlyinoculated lawn-spreads of S. aureus bacteria, and it was found afterovernight incubation that there was no inhibition of bacterial growth inthe areas where the solutions were placed. This indicates that there isno significant leaching of antimicrobial components (such as HP or zinc)into the solutions. Accordingly, the antimicrobial effects describedbelow are from contact of the bacteria with the solid gel formed byabsorption of PBS into the SAP powders. In other words, the mechanismdoes not appear to be a result of HP simply being trapped inside thedried SAP matrix, or release of sequestered HP from the antimicrobialcomposition.

Example 11 Evaluation of Antimicrobial Performance of SAP Materials

Each sample was evaluated in triplicate. Experimental powders (0.25 g)were weighed into 50-ml conical polypropylene centrifuge tubes and 11.5mL of PBS (phosphate buffered saline, 1×, Fisher Scientific #BP-399-1)was added to each tube by pipette. Untreated SAP control test sampleswere prepared similarly in triplicate. A 10⁻¹ inoculum of Escherichiacoli (ATCC #15597) or Staphylococcus aureus (ATCC #6538) was preparedfrom a 10⁻² dilution of an overnight culture in TSB (tryptic soy broth,Becton Dickinson Bacto™, REF 211825) of a glycerol stock. To each tubecontaining the powders to be tested, 1 mL of inoculum was added. Tubeswere vortexed for 10 seconds and then placed on a vertical rotatingwheel and rotated at 25 rpm for 24 hours at room temperature. Tubes werethen removed from the wheel and 10 mL of Letheen broth was added to eachtube by pipette. Tubes were vortexed at the maximum speed for 30seconds. Dilutions were then made and plated on appropriate agar usingthe standard pour plate method. Plates were incubated at 37° C.overnight, and then the bacterial colonies were enumerated. The resultsare summarized below, and expressed as “log reduction” of viableorganisms, in comparison to the growth observed in the tubes containinguntreated SAP powder.

Sample# Description Avg. Log Reduction Organism ZNP-1 ZA + HP 6.21* ECZNP-1 ZA + HP 5.96* SA ZNP-2B ZA + HP 6.21* EC ZNP-2C ZA 1.75 EC ZNP-2DHP 5.61 EC HP1-A HP 6.49* EC HP1-B HP 6.49* EC 121208C HP on CMC 6.49*EC SA = S. Aureus EC = E. Coli HP = Hydrogen Peroxide ZA = Zinc Acetate*= Full Kill

The above results indicate that HP is the primary agent responsible forthe antimicrobial activity, and that the antimicrobial contribution bythe zinc component is minimal.

Example 12 Evaluation of Antimicrobial Performance of SAP MaterialsAfter Prolonged Storage

The materials and procedures of Example 11 were used. Antimicrobial SAPmaterials were stored in sealed containers at room temperature for eight(8) months, and then tested for antimicrobial activity. The followingresults were obtained, which indicate that the materials are stableduring storage:

Sample# Description Avg. Log Reduction Organism ZNP-1 ZA + HP 7.08* ECZNP-2B ZA + HP 7.08* EC ZNP-2C ZA 2.08 EC ZNP-2D HP 7.08* EC EC = E.Coli HP = Hydrogen Peroxide ZA = Zinc Acetate *= Full Kill

Example 13 Iodometric Titration of Antimicrobial SAP Powders toDemonstrate and Quantify Sequestration of HP, and Non-LeachingProperties

Antimicrobial SAP powders described in the above examples were titratedto determine the amount of HP contained therein which is available forantimicrobial action. All SAP powders had been stored for greater thanone year prior to titration.

Principle: Hydrogen peroxide in the sample reacts with excess iodide inthe presence of an ammonium molybdate catalyst to stoichiometricallyproduce triiodide ions. The triiodide ion concentration is thendetermined titrimetrically with a standard thiosulfate solution. Thefollowing method was adapted from methods published by Solvay Chemicals.Inc. [TDS HH-125 “Determination of Hydrogen Peroxide (H2O2) Residual inFiber Matrices”, and TDS XX-122, “Determination of Hydrogen PeroxideConcentration (0.1% to 5%)”].Preparation of Reagents: all Reagents Used were Analytical Reagent Gradeand only deionized water was used

-   -   1. Potassium iodide (10%): In a 2-L beaker, 100 g of potassium        iodide (KI) was dissolved in 1000 mL of water, and stored in a        dark glass or opaque, capped bottle.    -   2. Acid Mixture: In a 2-L beaker, was dissolved 0.18 g of        ammonium molybdate ((NH₄)₆ Mo₇O₂₄.4H₂O) in 750 mL of water.        While stirring, 300 mL of concentrated sulfuric acid (H₂SO₄) was        slowly added, and stored in a glass container.    -   3. Sodium Thiosulfate Solution (0.100N): 49.63 g of sodium        thiosulfate (Na₂S₂O₃.5 H₂O) was transferred to a 2-L volumetric        flask, and 400 mL of water was added and agitated until        dissolution was complete, and diluted to volume, mixed well, and        stored in an amber or opaque, capped bottle.

The normality of this solution remained between 0.099 N and 0.101 N forat least one month. Alternatively, standard sodium thiosulfate solutionwas purchased from a laboratory supply company.

Starch Solution (10 g/L): One gram of soluble starch was weighed into a150-mL beaker. While stirring, about 5 mL of water was gradually addeduntil a paste formed. The paste was then added to 100 mL of boilingwater. The mixture was cooled, 5 g of potassium iodide (KI) was added,and stirred until dissolution was complete, and then transferred to aplastic bottle. The Following Analysis Procedure was then followed:

-   -   1. Weigh 1 g of antimicrobial SAP powder (“sample”) into a        125-mL Erlenmeyer flask. Record sample weight to the nearest        0.01 g.    -   2. Add 50 mL of distilled water and swirl for 15 seconds to mix.    -   3. Place flask in a water bath and heat at 50 C, while        agitating, for 2 hours. Let cool for 15 minutes.    -   4. Add 20 mL of 10% potassium iodide solution to the flask.        Swirl to mix.    -   5. Add 25 mL of H₂SO₄/ammonium molybdate solution to the flask.        Swirl to mix.    -   6. Let stand for 5 minutes.    -   7. Using a magnetic stirrer, begin stirring the slurry.    -   8. Using a 50-mL class-A burette, titrate the flask contents        with the standard 0.100 N sodium thiosulfate solution until the        color turns to a bright yellow hue.    -   9. Add a few drops of starch indicator to the flask.    -   10. Resume titrating until the dark blue color of the solution        turns clear.    -   11. Record the total volume of sodium thiosulfate dispensed as        ‘A_(o)’.    -   12. Repeat Steps 4 through 10 with pure water and record the        volume of sodium thiosulfate dispensed as ‘B’.    -   13. Let the slurry stand for a predetermined length of time to        measure the amount of additional sequestered HP that is released        (i.e. 24 hours, 48 hours, etc.). Resume stirring and titrate as        in Step 10, above. Record the total volume of sodium thiosulfate        as ‘A_(T)’.        The results were calculated according to the following:

${{Hydrogen}\mspace{14mu} {peroxide}},{{\% \mspace{14mu} w\text{/}w} = \frac{\left( {{\sum A_{i}} - B} \right)*(N)*(1.7007)}{C}}$

-   -   Where:        -   ΣA_(i)=sum of the titration volumes for sample (mL)        -   B=titration volume for blank (mL)        -   C=powder sample weight        -   N=normality of the sodium thiosulfate solution

Results:

The following results were obtained:

Initial [HP] [HP] @ [HP] @ Sample Name (%) 24 hours¹ (X) hours² ZnP-10.61 0.98 2.16 (144 h) ZnP-2B 0.51 0.51 — ZnP-2C (no HP) 0.09 0.09 —ZnP-2D (no Zn) 0.36 0.56 1.05 (120 h) ¹Cumulative % HP at 24 h²Cumulative % HP at indicated hours

The results clearly demonstrate that a significant amount of sequesteredactive HP is released from the samples, even after storage for over oneyear in the dry state. Furthermore, these results demonstrate thatactive HP is released in a sustained manner over a period of time (i.e.controlled-release of HP, which has oxidative or antimicrobial capacity)in the presence of an oxidative demand (in this case the presences ofiodide ion).

In light of the general disclosure provided herein above, with respectto the manner of practicing this inventive method, those skilled in theart will appreciate that this disclosure enables the practice of theinventive method according to the aspects and embodiments disclosedabove. However, the following experimental details are provided toensure a complete written description of this invention, including thebest mode thereof. However, it will be appreciated that the scope ofthis invention should not be construed in terms of the specific examplesprovided. Rather, the scope of this invention is to be apprehended withreference to the claims appended hereto, in light of the completedescription of this inventive method constituted by this entiredisclosure.

It is to be understood that the present invention may have various otherembodiments. Furthermore, while the form of the invention herein shownand described constitutes a preferred embodiment of the invention, it isnot intended to illustrate all possible forms thereof. It will also beunderstood that the words used are words of description rather thanlimitation, and that various changes may be made without departing fromthe spirit and scope of the invention disclosed. The scope of theinvention should not be limited solely to the examples given.

1. A polymeric composition comprising sequestered peroxide, produced bytreating a superabsorbent polymer with at least 0.005 grams of hydrogenperoxide per gram of superabsorbent polymer, wherein said treatmentcomprises swelling the superabsorbent polymer with an aqueous treatmentsolution comprising aqueous hydrogen peroxide, followed by drying. 2.The polymeric composition of claim 1 wherein said superabsorbent polymerwas treated with 0.01 to 0.15 grams of hydrogen peroxide per gram ofsuperabsorbent polymer.
 3. The polymeric composition of claim 2 whereinsaid superabsorbent polymer was treated with 0.02 to 0.15 grams ofhydrogen peroxide per gram of superabsorbent polymer.
 4. The polymericcomposition of claim 1, wherein said aqueous treatment solution furthercomprises a metal salt in an amount suitable to treat saidsuperabsorbent polymer with at least 0.02 grams of the metal salt pergram of superabsorbent polymer, and wherein said metal salt is selectedfrom the group consisting of zinc, magnesium, silver, copper, andzirconium salts.
 5. The polymeric composition of claim 4, wherein saidmetal salt in said aqueous treatment solution is an acetate saltselected from the group of zinc acetate, magnesium acetate, andzirconium acetate.
 6. The polymeric composition of claim 5, wherein saidmetal salt is zinc acetate or magnesium acetate.
 7. The polymericcomposition of claim 1, wherein said superabsorbent polymer is acarboxylate-containing polymer, a cellulose derivative, apolyacrylamide, or a polydiallyldialkylammonium salt.
 8. The polymericcomposition of claim 1, wherein said superabsorbent polymer is anacrylic acid-based polymer.
 9. The polymeric composition of claim 8,wherein said acrylic acid-based polymer is a cross-linked hydrophilicsodium salt form of a partially neutralized acrylic acid polymer. 10.The polymeric composition of claim 4, wherein said superabsorbentpolymer is a carboxylate-containing polymer, a cellulose derivative, apolyacrylamide, or a polydiallyldialkylammonium salt.
 11. The polymericcomposition of claim 6, wherein said superabsorbent polymer is acarboxylate-containing polymer, a cellulose derivative, apolyacrylamide, or a polydiallyldialkylammonium salt.
 12. The polymericcomposition of claim 11, wherein said carboxylate-containing polymer isa cross-linked hydrophilic sodium salt form of a partially neutralizedacrylic acid polymer.
 13. The polymeric composition of claim 1, whereinsaid polymeric composition is superabsorbent.
 14. An antimicrobialcomposition produced by treating a superabsorbent polymer with at least0.005 grams of hydrogen peroxide per gram of superabsorbent polymer,wherein said treatment comprises swelling the superabsorbent polymerwith an aqueous treatment solution of hydrogen peroxide, followed bydrying of the treated superabsorbent polymer, whereby addition of 0.2grams of the antimicrobial composition to approximately 1,000,000 viablebacteria in an aqueous liquid produces a 3-log reduction of viablebacteria in said aqueous liquid.
 15. The antimicrobial composition ofclaim 14, wherein said superabsorbent polymer is treated with 0.01 to0.15 grams of hydrogen peroxide per gram of superabsorbent polymer. 16.The antimicrobial composition of claim 15, wherein said superabsorbentpolymer is treated with 0.02 to 0.15 grams of hydrogen peroxide per gramof superabsorbent polymer.
 17. The antimicrobial composition of claim14, wherein said aqueous treatment solution further comprises a metalsalt, in an amount suitable to treat said superabsorbent polymer with atleast 0.02 grams of the metal salt per gram of superabsorbent polymer,and wherein said metal salt is selected from the group consisting ofzinc, magnesium, silver, copper, and zirconium salts.
 18. Theantimicrobial composition of claim 17, wherein said metal salt in saidaqueous treatment solution is an acetate salt selected from the group ofzinc acetate, magnesium acetate, and zirconium acetate.
 19. Theantimicrobial composition of claim 18, wherein said metal salt is zincacetate or magnesium acetate.
 20. The antimicrobial composition of claim14, wherein said superabsorbent polymer is a carboxylate-containingpolymer, a cellulose derivative, a polyacrylamide, or apolydiallyldialkylammonium salt.
 21. The antimicrobial composition ofclaim 14, wherein said superabsorbent polymer is an acrylic acid-basedpolymer.
 22. The antimicrobial composition of claim 21, wherein saidacrylic acid-based polymer is a cross-linked hydrophilic sodium saltform of a partially neutralized acrylic acid polymer.
 23. Theantimicrobial composition of claim 17, wherein said superabsorbentpolymer is a carboxylate-containing polymer, a cellulose derivative, apolyacrylamide, or a polydiallyldialkylammonium salt.
 24. Theantimicrobial composition of claim 19, wherein said superabsorbentpolymer is a carboxylate-containing polymer, a cellulose derivative, apolyacrylamide, or a polydiallyldialkylammonium salt.
 25. Theantimicrobial composition of claim 24, wherein said superabsorbentpolymer is a cross-linked hydrophilic sodium salt form of a partiallyneutralized acrylic acid polymer.
 26. The antimicrobial composition ofclaim 14, wherein said superabsorbent polymer is in the form of a powderor granular material.
 27. The antimicrobial composition of claim 14,wherein said superabsorbent polymer is superabsorbent after treatment.28. The antimicrobial composition of claim 14, wherein the antimicrobialactivity of the composition is non-leachable.
 29. The antimicrobialcomposition of claim 17, wherein the antimicrobial activity of thecomposition is non-leachable.
 30. The antimicrobial composition of claim22, wherein the antimicrobial activity of the composition isnon-leachable.
 31. A bandage, wound dressing, tampon, sanitary napkin,diaper, wipe, incontinence device or garment, food packaging, or medicaldevice, comprising the polymeric composition of claim
 1. 32. A bandage,wound dressing, tampon, sanitary napkin, diaper, wipe, incontinencedevice or garment, food packaging, or medical device, comprising theantimicrobial composition of claim
 4. 33. A bandage, wound dressing,tampon, sanitary napkin, diaper, wipe, incontinence device or garment,food packaging, or medical device, comprising the antimicrobialcomposition of claim
 14. 34. A bandage, wound dressing, tampon, sanitarynapkin, diaper, wipe, incontinence device or garment, food packaging, ormedical device, comprising the antimicrobial composition of claim 17.35. A method of making a polymeric composition comprising the steps: a.swelling a superabsorbent polymer with an aqueous treatment solutioncomprising at least 0.005 grams of hydrogen peroxide per gram ofsuperabsorbent polymer, and b. drying the polymer, whereby hydrogenperoxide is sequestered within or on the surface of said superabsorbentpolymer.
 36. The method of claim 35, wherein said aqueous treatmentsolution comprises 0.02 to 0.15 grams of hydrogen peroxide per gram ofsuperabsorbent polymer.
 37. The method of claim 35, wherein said aqueoustreatment solution further comprises an amount of a metal salt suitableto treat said superabsorbent polymer with at least 0.02 grams of saidmetal salt per gram of said superabsorbent polymer, wherein said metalsalt is selected from the group consisting of zinc, magnesium, silver,copper, and zirconium salts.
 38. The method of claim 37, wherein saidmetal salt in said aqueous treatment solution is an acetate saltselected from the group of zinc acetate, magnesium acetate, andzirconium acetate.
 39. The method of claim 38, wherein said metal saltis zinc acetate or magnesium acetate.
 40. The method of claim 35,wherein said superabsorbent polymer is a carboxylate-containing polymer,a cellulose derivative, a polyacrylamide, or apolydiallyldialkylammonium salt.
 41. The method of claim 35, whereinsaid superabsorbent polymer is an acrylic acid-based polymer.
 42. Themethod of claim 41, wherein said acrylic acid-based polymer is across-linked hydrophilic sodium salt form of a partially neutralizedacrylic acid polymer.
 43. A method of making a superabsorbentantimicrobial composition comprising the steps: a. swelling asuperabsorbent polymer with an aqueous treatment solution comprising atleast 0.005 grams of hydrogen peroxide per gram of superabsorbentpolymer, and b. drying the polymer, whereby said superabsorbentantimicrobial composition having non-leachable antimicrobial activity isproduced and whereby contact with said superabsorbent antimicrobialcomposition provides at least a 3 log reduction in viable bacteria. 44.The method of claim 43, wherein said aqueous treatment solutioncomprises 0.02 to 0.15 grams of hydrogen peroxide per gram ofsuperabsorbent polymer.
 45. The method of claim 43, wherein said aqueoustreatment solution further comprises an amount of a metal salt suitableto treat said superabsorbent polymer with at least 0.02 grams of saidmetal salt per gram of said superabsorbent polymer, wherein said metalsalt is selected from the group consisting of zinc, magnesium, silver,copper, and zirconium salts.
 46. The method of claim 45, wherein saidmetal salt in said aqueous treatment solution is an acetate saltselected from the group of zinc acetate, magnesium acetate, andzirconium acetate.
 47. The method of claim 46, wherein said metal saltis zinc acetate or magnesium acetate.
 48. The method of claim 43,wherein said superabsorbent polymer is a carboxylate-containing polymer,a cellulose derivative, a polyacrylamide, or apolydiallyldialkylammonium salt.
 49. The method of claim 43, whereinsaid superabsorbent polymer is an acrylic acid-based polymer.
 50. Themethod of claim 49, wherein said acrylic acid-based polymer is across-linked hydrophilic sodium salt form of a partially neutralizedacrylic acid polymer.
 51. A method of disinfecting an infected liquid toproduce a 3-log reduction in viable bacteria therein, which comprisescontacting the liquid with an antimicrobial composition of claim
 14. 52.A method of disinfecting an infected liquid to produce a 3-log reductionin viable bacteria therein, which comprises contacting the liquid withan antimicrobial composition of claim
 17. 53. A method of disinfectingan infected liquid to produce a 3-log reduction in viable bacteriatherein, which comprises contacting the liquid with an antimicrobialcomposition of claim
 20. 54. A method of controlling diaper rash byusing a diaper or incontinence garment of claim
 31. 55. A method ofcontrolling diaper rash by using a diaper or incontinence garment ofclaim
 32. 56. A method of controlling diaper rash by using a diaper orincontinence garment of claim
 33. 57. The method of claim 51, whereinsaid method reduces or controls odor, infection, microbial rashes, orallergies.
 58. The method of claim 52, wherein said method reduces orcontrols odor, infection, microbial rashes, or allergies
 59. The methodof claim 35, wherein the aqueous treatment solution is at least 5 timesthe weight of the superabsorbent polymer.
 60. The method of claim 43,wherein the aqueous treatment solution is at least 5 times the weight ofthe superabsorbent polymer.